@[TOC]背景

ubuntu下go build 出错：

# github.com/h2non/bimg
/tmp/go-build2910330990/b131/_x005.o: In function `vips_reduce_bridge':
../../pkg/mod/github.com/h2non/bimg@v1.1.9/vips.h:133: undefined reference to `vips_reduce'
collect2: error: ld returned 1 exit status
# github.com/h2non/bimg
In file included from ../../pkg/mod/github.com/h2non/bimg@v1.1.9/vips.go:5:0:
../../pkg/mod/github.com/h2non/bimg@v1.1.9/vips.h: In function ‘vips_reduce_bridge’:
../../pkg/mod/github.com/h2non/bimg@v1.1.9/vips.h:133:9: warning: implicit declaration of function ‘vips_reduce’ [-Wimplicit-function-declaration]
return vips_reduce(in, out, xshrink, yshrink, NULL);
^

@[TOC]主要原因

https://github.com/deso-protocol/backend/issues/84

https://github.com/libvips/libvips/issues/1844

即需要更新libvips包到高版本（最新也可）。如未安装该包，则会提示：

No package 'vips' found
Package vips was not found in the pkg-config search path.
Perhaps you should add the directory containing `vips.pc'
to the PKG_CONFIG_PATH environment variable
No package 'vips' found
pkg-config: exit status 1

install一下即可解决。

@[TOC]排查手段

查看版本（成功时）

vips -v
vips-8.2.2-Sat Jan 30 17:12:08 UTC 2016

如未安装则会提示。

@[TOC]解决办法

首先安装几个必要的包：

apt-get install  build-essential  libvips-dev libglib2.0-dev  libexpat1-dev

备份源

cp  /etc/apt/sources.list  /etc/apt/sources.list.bk

更新源

vim /etc/apt/sources.list

内容如下:

deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

执行更新：

sudo apt-get update

可先尝试更新libvips-dev

apt-get upgrade libvips-dev

如有报错 或 更新成功了但尝试再次编译还是不成功的话，继续看下一步。

按依赖识别更新所有包：

apt-get dist-upgrade

再次查看

vips -v
vips-8.4.5-Wed Jan 18 12:36:44 UTC 2017

可以看到本部已更新。

@[TOC]最终成功时的pkg-config的环境变量

export PKG_CONFIG_PATH=/usr/lib/x86_64-linux-gnu/pkgconfig